Abundant algae fouling S.J. River potentially toxic

Not that anyone would confuse Stockton's polluted downtown channel with a pristine stream.

Alex Breitler

Not that anyone would confuse Stockton's polluted downtown channel with a pristine stream.

But in the past few weeks, the sickly channel has been looking greener than normal.

A state official confirmed Friday that a potentially toxic form of blue-green algae is blooming in the San Joaquin River. It's unknown whether this is the same algae greening up the waterfront area only a few miles away.

But in general, "This year is quite bad," said Peggy Lehman, an environmental scientist with the state Department of Water Resources.

The algae thrives on a mixture of warm water, light and nutrients, such as fertilizer from farmers' fields.

Add in low river flows because of the drought, and we could have a bumper crop of algae this summer.

The Microcystis species that is blooming right now in the San Joaquin can be toxic, potentially causing cancer if ingested by humans and wildlife.

Simply touching algae-laden water can cause rashes and irritation. "People should be very careful," Lehman said, adding that boating in general should be OK.

Scientists also continue to study whether these algae are responsible, at least in part, for the decline of certain Delta fish species.

The extent of the algae outbreak is still unclear, Lehman said. Any health warnings, if necessary, will be issued at the county level.

Dianna Carroll, 50, of Lodi leaned over a railing near the Stockton Marina earlier this week and peered into the scummy water. A year ago, she took a 10-minute dip farther north in the Delta, in the Mokelumne River, and later became nauseated for several days.

Any number of things could have caused that.

"But it was my daughter and I who went swimming," Carroll said. "Only two of us got into the water. And we both got sick."

Microcystis has been in the Delta for only about 15 years. But 68-year-old Bob Wright, who lives in a custom-made paddle-wheel boat on the north bank of the downtown channel near Interstate 5, said the problem goes back much longer than that.

"Thirty years ago you'd have algae clumps the size of a football or the size of a medicine ball," Wright said.

Bubblers since installed by the city near the channel head helped with water quality, he said.

But this is our third year of drought. There is little runoff to freshen the Delta, not to mention the dead-end downtown channel.

"This year is definitely worse than last year," Wright said. "This is what you get if you never flush the channel. But I guess I've just learned to live with it."

Contact reporter Alex Breitler at (209) 546-8295 or abreitler@recordnet.com. Follow him at recordnet.com/breitlerblog and on Twitter @alexbreitler.